1. Field of the Invention
The present invention relates to apparatus and method for clamping a fuel injector in place on an internal combustion engine and an engine including such apparatus.
A clamp for an internal combustion engine injector must securely retain the injector against the forces generated within the engine cylinder and the clamping means must be readily accessible for installation and removal of the injector.
The technical and commercial advantages associated with minimising engine envelope size and the increasing fitment of multi-camshaft and multi-valve systems have reduced the available space for fitting a clamp retaining means closely adjacent to the injector, this being particularly the case in engines fitted with relatively large injectors as exampled by hydraulically or mechanically actuated and electronically controlled unit injectors. This provides an incentive for fitting clamp retaining means away from the injector if possible.
A further problem can arise if the injector clamping counterload is directed into an area of the engine located near the injector insertion point in the cylinder head. For example, any threaded holes provided for clamp retaining fasteners which are located adjacent to the injector may weaken a critical part of the cylinder head or may break through into an injector coolant jacket and thus require sealing against leakage. In these circumstances, it is again advantageous if the injector clamping counterload is located away from this critical area.
Further, injector removal and refitment may be required during engine servicing and it is therefore beneficial to minimise impedance to access and the time required for injector removal and refitment. In the prior art, the operations of fitting or removing a unit injector have generally required the complete removal and replacement of one or more threaded fasteners and hence, particularly in an engine with a high number of injectors, these operations are undesirably time consuming.
2. Description of the Related Art
An example of prior art means for clamping hydraulically actuated, electronically controlled, unit injectors may be seen in U.S. Pat. No. 5,499,612. Clamping means for other types of injectors may be seen in GB 2213197, U.S. Pat. Nos. 4,206,725 and 4,246,877.